Roman Numerals

 Counting . . . we all do it many times every day. We count our stuffed animals, forks needed for setting the table, and our number of hits in the big game.    From the earliest time, man has had a need to count.  How many dinosaurs are headed our way?  How many children are in our cave? Have you ever wondered how people counted before we had numerals? They counted on their fingers.  They made lines in the dirt.   One early counting system used beads or stones arranged in rows.

About 2,000 years ago, the Romans developed a system of counting that is very much like the decimal system of counting that we use today. Click on the blue Roman numeral to see how the two systems are alike.
 A symbol is used to stand for a   number. II. The place of the symbol helps   determine the value of the numeral. Symbols are added and subtracted to   determine the value. Always read from left to right. Roman Numerals

All numerals can be written by combining these symbols that the Romans used.

 Roman numerals Decimal numerals I 1 V 5 X 10 L 50 C 100

Romans added and subtracted their numerals to show the exact value that was needed.

VI means 5+1 so
VI means 6

IV means 5-1 so
IV means 4

Add to find the value of each Roman numeral.

III means 1+1+1 so
III =

LXI means 50 + 10 + 1 so
LXI=

CC = XVI = CLX =

CX = CV = XX =

 Roman numerals Decimal numerals I 1 V 5 X 10 L 50 C 100

Subtracting

If a smaller numeral is to the left, subtract
it from the larger numeral to the right.

IV means 1 subtracted from 5 so
IV = 4

XL means 10 subtracted from 50 so
XL = 40

IX means 1 subtracted from 10 so
IX = 9

 Roman numerals Decimal numerals I 1 V 5 X 10 L 50 C 100

Subtract to find the value of each Roman numeral.

IX means 1 from 10 so
IX =

XL means 10 from 50 so
XL=

IV =      IC =       XC =

VL =      VC =      IL =

 Roman numeral Decimal numeral I 1 V 5 X 10 L 50 C 100

Many times we must add and subtract to find the value of a Roman numeral.

Remember: always start reading from the left.

CXL means
C = 100
XL = 10 from 50 = 40
CXL means 100 + 40 = 140

 Roman numerals Decimal numerals I 1 V 5 X 10 L 50 C 100

Add and subtract to find the value of these Roman numerals.

XIV means
X = 10
IV = 1 from 5 = 4
XIV = 10 + 4 =

CIV =  XLV =

XIX =  CCIX =

 Roman numerals Decimal numerals I 1 V 5 X 10 L 50 C 100

We can count using our decimal numerals and Roman numerals. Complete the chart below.

 Roman numeral I II 2 III IIII IV VI V 6 IV VI VII VIII 8 IX VV X 10 Decimal numeral 1 2 3 4 5 6 7 8 9 10  Complete the chart below. Remember the placement of the numerals tells us when to add or subtract.

 Roman numeral XX XI IX XII XIII 13 14 XIIII XIV XV VX 15 XVI XVII XVIII 19 XXI XIX XX VV 20 Decimal numeral 11 12 13 14 15 16 17 18 19 20

 How is our decimal number system like the Roman number system?  Click on the Roman soldier for a reminder, then type a sentence that tells how the two number systems are alike. Click the Done button when you are finished.    As you are roaming around through your favorite books, look for Roman numerals as page numbers or chapter numbers. Now you will know the value of the numerals.